Wet blasting apparatus



Jan., 26, 1954 w. l. GLADFELTER E-rAL 2,667,014

WET BLASTING APPARATUS 2 sham-sheet 1 Filed June 29, 1951 FIGURE 2 um, L um Mp. L 6m LR em .H C Ld l wm IN VEN TORS WM@ ATTORNEY Jan. 26, 1954 Filed June 29. 1951 FIGURE 3 W. I. GLADFELTER v ET AL 2,667,014

WET BLASTING APPARATUS 2 Sheets-Sheet 2 WILT/E GLADFELTER and CHARLES A CROFT JNVENToRs lex/@M A TTORNEY Patented Jan. 26, 1954 OFFICE 2,667,014 WET BLASTIN G APPARATUS Wiltie I. Gladfelter and Charles P. Croft,

Hagerstown, Md.

Application June 29, 1951,

Serial N0. 234,392

12 claims. (C1. 51-8) The present invention relates to blasting apparatus and particularly to those types of apparatus in which a stream of blastant particles mixed with liquid is projected against work articles to clean or modify the surface of these articles.

Blasting apparatus of this type have previously been heavily burdened by the fact that they use tremendous volumes of liquid and accordingly involve considerable expense even when this liquid is ordinary tap water.

Among the objects of the present invention is the provision of novel blasting apparatus of the above type which avoids the above disadvantage, as well as the provision of novel components of such apparatus.

The above as Well as additional objects of the present invention will be more completely understood from the following description of several of its exemplications, reference being made to the accompanying drawings wherein:

Fig. 1 is a plan view, in outline form, of a blasting apparatus illustrating the present invention;

Fig. 2 is a side elevation, with parts in section, of a portion of the apparatus of Fig. 1; and

Fig. 3 is a plan view partly broken away of the structure of Fig. 2.

According to the present invention there is provided a blasting apparatus having a blast projector with impelling structurefconnected to project against work articles a stream of blastant particles mixed with liquid, and recycling structure connected to collect the projected blastant material, separate out most of the liquid, clarify the separated liquid and return the claried liquid for additional blasting. In order to clarify the liquid for reuse in blasting, chemical clarifying material may be added and the clarifying structure may include a settling tank, inlet structure for the introduction of Water clarifying material and water to be clarified, agitating structure adjacent said inlet structure and connected to mix the introduced materials and discharge the mixed materials into the body of the settling tank, louvres in the settling tank defining a relatively quiescent zone in which settling of the sludge takes place, said tank having outlet structure for discharging the claried water after settling, and conveyor mechanism connected for removing the sludge settling through the louvres.

The apparatus of Fig. 1 is shown as including a blasting chamber IU equipped with a blasting nozzle I2 and a work-carrying platform shown as a table I4. Work articles are arranged to be introduced in the chamber I Il and on to platform I 4 plies Water at pressures of per square inch, along with the blastant particles against the work articles being treated. If desired a slurry at least 500 pounds 2,503,743, granted April ll, 195i).

The door of chamber i0 .is shaped to collect the projected blastant materials after they drain from the work articles and funnel them-to a coarse separator indicated generally `atll. effect this funneling the floor of chamber I0 is shown in Fig. 1 as having a tapered central trough 22 with a depressed outlet 24, the .coarse separator 3i) being positioned below this outlet as by being located in a pit excavated in the oor alongside chamber I0. Work supporting Vholder I4 need not be iixed directly within trough 22 but may be held above it as by chamber oor which can Y Y form of a metal gridwork. If desired, this chamber floor may have rails on which the work supporting structure can be rolled inand out of the chamber, particularly where the work articles are of the bulky type and can be mounted on railmounted cars or wheel trucks.

The coarse separator 30 is shown as including a rotatable cylindrical screen 32 into one end of which the trough outlet 24 supplies collected blastant, and the walls of which have perforations 34 large enough to permit the blastant particles and the water to drop through into a re- Which is removed from the work articles by the blasting operation, discharge from the other end of the cylindrical screen 32 into a waste receiver 38 for manual or automatic, and continuous or intermittent removal.

An impelling pump d connected with the lower portion of receptacle 36, rwhich maybe tapered'in hopper fashion, moves the collected blastant and the water through line d2 to a classifier 50. 'Ihe classier which can beef; the u sual kind has a The nozzle I2 is connected` a high-pressure pump I3'.

preferably higher; and impels itl means of a perforated' supply line |02 coarse slurry outlet 52 through which the coarser blastant particles along with some of the liquid are discharged in the form of a slurry for storage in a tank 54 or removal by means of receptacle 50. A liquid or fine slurry outlet 58 from classiier 50 discharges the finer blastant particles along .vith the balance of the collected liquid to a clarieiindicated generally at 10 and more particularly shown in Figs. 2 and 3.

Clarifier 10 comprises an elongated tank 12 of generally rectangular form with a oor 15 that tapers up at one end 14 and leads to a discharge spout 16. Conduit 58 introduces thefine slurry over the tapering portion 14 of the floor where a coarse particle trapping screen-11 can be pro-- vided in the form of a removable basket.

Within the tank adjacent the portion at which conduit 58 empties, a pair of agitators 808I are positioned. These agitators are shown as assemblies of varies 82, held between side discs B4 in generally cylindrical relation, and rotated around the axis of the cylinder which is horizontally dis posed. Both agitators 80, 8| are shown as rotated in either the sameor different directions and either clockwise or counter-clockwise as by means of an electric motor 06, belts 88 and 90, and appropriately provided pulleys. Violent agitation is preferred. l

Adjacent these agitators an external electrolyzing container communicates with the interior of tank 12 and is provided with a separate water and a set of electrodes |234, connected to a suitable source of direct electric current, not shown, at a potential of at least about volts. One of the electrodes |04, |05 is of aluminum or aluminum alloy composition, and this electrode is connected as the anode so that electrolytic anodic oxidation products of aluminum are formed in the water in container |00. The electrolyzed water containing the anodic oxidation products is introduced into-the tank 12 along with the iine slurrydischarged through conduit 58 and-these two supplies are particularly well mixed when one of the agitators, asfor example agitator 80, is rotated at a slower speed than its companion agitator. Baies as indicated at 92, 94, 90 and 98 connue-the more vigorous portions of the agitations tothe regions closely adjoining the agitators and permit the introduced fluids to move intothe main body of the tank where they are relatively free of turbulence and pass without appreciable agitation out over an overflow spout |20.

In the body of the tankl the larger or the suspended particles that are supplied in the fine slurry settle under the influence of gravity assisted by the clarifying action of the added clarifier such as the anodic aluminum oxidation products described above. A set of louvres |22 shown as spaced inverted V-shaped angular plates, are disposed above the floor 15 and effect a waterbaling action suicient to define a relatively quiescent zone through which the settling particles move very readily to the bottom or the tank.

The louvres |22 are spaced above the tank floor 15 and in this space is threaded a sludge conveyor shown in the form ofv a pair of chains |32, |34 looped around sprockets |40, |4|, |42, |43, |44 and |45, and carrying a set of laterally extending spaced drag plates |50. The conveyor is cycled slowly as by providing sprocket |43 with a pulley |52 connected by belt |54 w th motor 8'5. The drag plates, as they move along the tank ioor 15, carry the settled sludge along with them up the sloping section 14 and into the top of spout 16. A scraper blade |60 pivoted at support |62 and counterbalanced as by means of weight |64 engages the individual drag plates as they move through the top of spout 15 and scrapes off any sludge adhering to them. A stop |66 having a silencing bumper |68 can be effectively used to properly position the scraper blade for engagement by the drag plates and to assure that this blade returns to its proper position after it is deflected by a passing plate.

The clarifying material used in accordance with the present invention is not limited to the elec trolytic oxidation products described above but can be of any suitable kind such as stoichiometric mixturesfof aluminum sulphate and calcium hydroxide. However, the electrolytic unit is particularly ecacious It not only reduces the amount o f the sludge, which normally accumulates at an extremely rapid rate, but makes possible the compacting of the entire clarifying apparatus.`

From the overflow spout |20, the clarified water passes through fine mesh screen |12 into a head box |14from which it returns to the intake of the high-pressure pump by means of conduit |16 or discharges at conduit |18 to waste. A float valve responsive to the level of liquid in the head box |14 shuts off or adds a controllable amount of replenishing water from conduit |82 in accordance with the supply of claried water available.

The claried out-flow in head box |14 need not be entirely free of blastant particles. Particles as fine as about 360 mesh or finer present no diiriculties and can be carried along with the recirculating pump i8 and back into the blasting cycle. Coarser particles cause serious abrasion of the pump but are effectively removed from the recirculating water in the clarifier. This partial clarification enables a considerable shortening of the settling time in the clarer tank so that a relatively small clarifying apparatus is all that is needed to handle the large volumes of liquid involved inl the blasting.

In practical applicationl blastant particles are generally between about 40 and about 250 mesh in size, and are common sand, although other types of gritty material can also be used. The classifier 50 should be adjusted so that it separates out 'a thick slurry of particles having a size corresponding to those originally delivered to the blast projector, leaving 'ner particles to be carried out with the excess water. This not only reduces the clarifying action required, but causes least Waste of blastant.

The particular details of the blasting chamber l0 and nozzle I2 form no part of the present invention. Any suitable combination can be used with the recirculating apparatus shown. Thus, for example, the blasting nozzle can be arranged either to swivel about as indicated in the drawings, or can be slidable along the chamber wall, or can be both slidable and swiveled in order to be readily directable from any desired angle on the work pieces. Alternatively, the nozzle can also be ixed in place and the work pieces rotated or otherwise moved, as for example by revolving table i4 around a central vertical axis.

To complete the automatic recirculation a slurry pump (not shown) such as the one shown at 40 is connected between tank 54 and the nozzle line 2i) to return the coarser abrasive particles for further blasting. 1f desired the portions of the apparatus can be relocated as by moving the nozzle to the opposite wall of chamber I0 so that liquid through the high-pressure` the classifier outlet 52 is positioned alongside the nozzle I2 and the recirculating slurry is pumped or sucked through a shorter length of conduit and be less likely to jam. Furthermore the classifier can have its outlet 52 high enough to supply part or all the desired slurry moving force by the action of gravity. Inasmuch as the operation of the equipment may result in the accumulation of additional abrasive particles as for example in the form of the mold and core sand that is removed from the work articles when they are castings being cleaned, the tank 55 can be used to collect excess abrasive particles.

To provide access to trough 22 underneath chamber I6, as for the purpose of cleaning it or removing large objects, this trough can be extended out at its upper end beyond the margins of chamber I as indicated at 23.

Many of the advantages of the present invention will be obvious. These include a substantial reduction in production cost for foundry work by reason of decreased casting-cleaning time, reduction in labor costs through permitting one-man operation, provision for complete recovery of the casting sand and core rods, complete elimination of dust, and a reduction in roughing and chipping costs.

A feature of the present invention, in addition to the blastant liquid recirculation, is that it becomes economically practical to add treating agents to the liquid to provide additional effects. Thus, rust inhibiting agents such as Zinc chromate can be dissolved in the blastant liquid to reduce corrosion of iron work articles, instead of using the usual protective after-treatments. Freshly wet-blastant articles are generally quite susceptible to corrosion and such protective measures are a necessity. In addition, the blastant liquid can be arranged to carry chemical cleaning agents such as detergents, emulsiers,

etc., to' improve the blasting action on soiled surfaces. Such additions are not feasible where the liquid is used only once and then discarded without recirculation.

be understood that this invention is not limited hereof except as dened in the appended claims.

What is claimed is:

1. A water clarifying apparatus including a settling tank, inlet structure for the introduction of Water clarifying material and water to be claritling of sludge takes place, said tank having outlet structure for discharging the clarified water after settling, and conveyor mechanism connected for removing the sludge settling through the louvres.

2. The combination as dened by claim 1 in which the inlet structure includes an electrolyzing container through which water is passed, and including an aluminum anode for electrolyzing the Water passing therethrough and introducing into the water anodic oxidation products of said electrode.

3. In a wet-blasting apparatus, a blasting maprojects against work articles a stream of liquid to work the surfaces of the articles and remove debris vtherefrom, collecting means for. collecting the projected blastant particles and liquid together with the debris from the 4work articles, separating said mixture and separate a thick slurry contain. l

ing the large sized particles of said blastant material from said mixture, a clarifying apparatus connected with said classifier to receive the remaining mixture therefrom and including structure for clarifying the liquid portion of the mixture, and recycling means connected to return the clarified liquid to the blasting machine for additional blasting.

4. The combination set forth in claim 3 in Which said separator includes a rotating perforated cylinder into which said mixture of blastant particles, liquid and-debris is discharged.

5. The combination set forth in'claim 3 in which said clarifier includes a settling tank having an inlet structure connected to said classifier and an agitating structure adjacent said inlet, said agitating structure including means for chemically clarifying said mixture and causing foreign materials in the liquid of said mixture to settle out.

6. A method for reusing a used wet-blasting mixture ejected from a wet-blasting apparatus impeller, said method comprising the steps of mechanically separating coarse debris particles from said mixture, then mechanically classifying the residual mixture into two separate portions slurry including reusable fines of blastant particles and foreign matter, mixing a water clarifying material with said second slurry, agitating said clarifying mixture settling said agitated mixture so as to cause precipitation of said ne blastant particlesand foreign matter, and mixing the thus claried water with blastant particles suitable for another blasting operation.

7. The method set forth in claim 6 including the further step of separately returning said clarified liquid and said thick slurry to the impelling structure of the wet-blasting apparatus.

8. The process set forth in claim 6, in Which said water clarifying material includes the electrolytic oxidation products of aluminum.

9. In a wet-blasting apparatus including a blasting machine having a blastant particle im- 7 .10,`The combination set forth in claim 9 in- Which the classifying means includes a mechanical separator and the clarifying means includes structure for introducing the electrolytic anodic oxidation products of aluminum into the said remaining mixture.-

11. A blastant'recirculating wet-blasting apparatus comprising a blasting machine having impelling structure connectedvto project against Work articles a stream of carrier liquid containing blastant particles and recirculating structure 112;I'h`e 'combination set forth in claim 1l in which separate conduit means are provided for recycling the segregated slurry of blastant materials and clarified carrier liquid respectively to said impelling structure.

WILTIE I. GLADFELTER. CHARLES P. CROFT.

References Cited in the file of this patent UNiTED STATES PATENTS Number Name Date 599,957 Curtis Mar. '1, 1898 1,519,250 Gelstharp Dec. 1S, 1924 1,907,411 Timoney May 2, v1933 1,966,571 Webb July 17, 1934 2,086,653 Watson et al July 13, 1937 2,200,587 Tirell May 14, 1940 2,393,596 Dexter Jan. 29, 1946 2,462,480 Eppler Feb. 22, 1949 

